android.view.WindowManager$BadTokenException: Unable to add window -- token null is not valid; is your activity running? 에러

android.view.WindowManager$BadTokenException: Unable to add window -- token null is not valid; is your activity running?

Dialog 생성 시 getApplicationContext()를 사용해서 나는 에러.

(Activity 이름).this로 변경하면 해결.